Should we continue to drain the pylorus in patients undergoing an esophagectomy?

A systematic review of the literature was performed to assess the necessity of a pyloric drainage procedure during an esophagectomy with gastric conduit reconstruction. Earlier data recommend performing a pyloric drainage procedure for all esophagectomies; however, recent studies have questioned this. A thorough literature search (January 2001-November 2011) was performed using the terms esophagectomy, pyloroplasty, pyloromyotomy, botulinum toxin, and pyloric drainage. Only studies that compared patient outcome after undergoing an esophagectomy with a pyloric drainage procedure with those undergoing an esophagectomy without a pyloric drainage procedure were selected. Only four studies, comprising 668 patients in total, were identified that compared patient outcome after undergoing an esophagectomy with or without a pyloric drainage procedure, and two additional meta-analyses were identified and selected for discussion. All studies were retrospective, and because of the heterogeneity of studies, patient demographics, reporting, and statistical analysis of patient outcome, pooling of data and meta-analysis could not be performed. Careful analysis demonstrated that pyloric drainage procedure was associated with a non-significant trend for delayed gastric emptying and biliary reflux, while not affecting the incidence of dumping. No correlation was determined between a pyloric drainage procedure and anastomotic leaks, postoperative pulmonary complications, length of hospital stay, and overall perioperative morbidity. While there are risks associated with a pyloric drainage procedure and data exist supporting its omission during an esophagectomy, no good conclusion can be drawn from the current literature. Larger multi-institutional, prospective studies are required to definitively answer this question.

Treatment with humanized monoclonal antibody against CD154 prevents acute renal allograft rejection in nonhuman primates.

CD154 is the ligand for the receptor CD40. This ligand-receptor pair mediates endothelial and antigen-presenting cell activation, and facilitates the interaction of these cells with T cells and platelets. We demonstrate here that administration of a CD154-specific monoclonal antibody (hu5C8) allows for renal allotransplantation in outbred, MHC-mismatched rhesus monkeys without acute rejection. The effect persisted for more than 10 months after therapy termination, and no additional drug was required to achieve extended graft survival. Indeed, the use of tacrolimus or chronic steroids seemed to antagonize the anti-rejection effect. Monkeys treated with antibody against CD154 remained healthy during and after therapy. The mechanism of action does not require global depletion of T or B cells. Long-term survivors lost their mixed lymphocyte reactivity in a donor-specific manner, but still formed donor-specific antibody and generated T cells that infiltrated the grafted organ without any obvious effect on graft function. Thus, therapy with antibody against CD154 is a promising agent for clinical use in human allotransplantation.

Influence of race on kidney transplantation in the Department of Defense healthcare system.

BACKGROUND: We report the influence of race on transplant outcomes in the Department of Defense (DOD) system. METHODS: Retrospective cohort analysis of all kidney transplants performed at WRAMC from 1996 to 2005. Kaplan-Meier analysis was used to assess for differences in graft survival, and Cox regression was used to calculate adjusted hazard ratios for graft loss. For our analyses, we used the cutoff of 6 years (year 2000) when we introduced thymoglobulin induction; maintenance immunosuppression consisted of mycophenolate mofetil and tacrolimus, and rapid steroid taper (completed withdrawal at 6 weeks) was used for all patients. RESULTS: There were 220 transplants (91 Blacks, 107 Caucasians and 22 Asians). Because the curve for graft survival for Blacks over time violated the proportional hazards assumption (at 6 years post-transplant), analysis was segregated into two segments. Through 6 years of follow-up, graft survival was 77% for Blacks and 81% for non-Blacks (p = 0.74 by log rank). Through 9 potential years of follow-up, graft survival for Blacks was 56% and 78% for Whites (p = 0.005). In Cox regression analysis, Black race, compared with non-Black race, was not significantly associated with graft loss at 6 years, but was significantly associated with graft loss occurring after 6 years. CONCLUSIONS: In the DOD health system, no significant differences were seen in graft survival among recipients of different races at 6 years. Black recipients who received a kidney transplant before the year 2000 showed decreased graft survival compared to non-Blacks. This was consistent with change in immunosuppressive regimen in our institution with the introduction of thymoglobulin induction and maintenance therapy with tacrolimus, mycophenolate mofetil and withdrawal of prednisone at 6 weeks.

Modular organization of genes required for complex polyketide biosynthesis.

In Saccharopolyspora erythraea, the genes that govern synthesis of the polyketide portion of the macrolide antibiotic erythromycin are organized in six repeated units that encode fatty acid synthase (FAS)-like activities. Each repeated unit is designated a module, and two modules are contained in a single open reading frame. A model for the synthesis of this complex polyketide is proposed, where each module encodes a functional synthase unit and each synthase unit participates specifically in one of the six FAS-like elongation steps required for formation of the polyketide. In addition, genetic organization and biochemical order of events appear to be colinear. Evidence for the model is provided by construction of a selected mutant and by isolation of a polyketide of predicted structure.

An erythromycin derivative produced by targeted gene disruption in Saccharopolyspora erythraea.

Derivatives of erythromycin with modifications at their C-6 position are generally sought for their increased stability at acid pH, which in turn may confer improved pharmacological properties. A recombinant mutant of the erythromycin-producing bacterium, Saccharopolyspora erythraea, produced an erythromycin derivative, 6-deoxyerythromycin A, that could not be obtained readily by chemical synthesis. This product resulted from targeted disruption of the gene, designated eryF (systematic nomenclature, CYP107), that apparently codes for the cytochrome P450, 6-deoxyerythronolide B (DEB) hydroxylase, which converts DEB to erythronolide B (EB). Enzymes normally acting on EB can process the alternative substrate DEB to form the biologically active erythromycin derivative lacking the C-6 hydroxyl group.

Gibberellic Acid Induces Vacuolar Acidification in Barley Aleurone.

The roles of gibberellic acid (GA3) and abscisic acid (ABA) in the regulation of vacuolar pH (pHv) in aleurone cells of barley were investigated using the pH-sensitive fluorescent dye 2[prime],7[prime]-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). BCECF accumulated in vacuoles of aleurone cells, but sequestration of the dye did not affect its sensitivity to pH. BCECF-loaded aleurone cells retained their ability to respond to both GA3 and ABA. The pHv of freshly isolated aleurone cells is 6.6, but after incubation in GA3, the pHv fell to 5.8. The pHv of cells not incubated in hormones or in the presence of ABA showed little or no acidification. The aleurone tonoplast contains both vacuolar ATPase and vacuolar pyrophosphatase, but the levels of pump proteins were not affected by incubation in the presence or absence of hormones. We conclude that GA3 affects the pHv in aleurone cells by altering the activities of tonoplast H+ pumps but not the amounts of pump proteins.

Rice root curling, a response to mechanosensing, is modulated by the rice E3-ubiquitin ligase HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE1 (OsHOS1).

Plant development depends on the perception of external cues, such as light, gravity, touch, wind or nutrients, among others. Nevertheless, little is known regarding signal transduction pathways integrating these stimuli. Recently, we have reported the involvement of a rice E3-ubiquitin ligase (OsHOS1, HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE1), previously associated with abiotic stress response, in root responses to mechanical stimuli. We showed that OsHOS1 is involved in the regulation of root curling after mechanosensing and that RNAi::OsHOS1 plants failed to exhibit the root curling phenotype observed in WT. Interestingly, the straight root phenotype of these transgenics correlated with the up-regulation of rice ROOT MEANDER CURLING (OsRMC, a negative regulator of rice root curling) and was reverted by the exogenous application of jasmonic acid. Altogether, our results highlight the role of the proteasome modulating plant responses to mechanical stimuli and suggest that OsHOS1 is a hub integrating environmental and hormonal signaling into plant growth and development.

Human serum amyloid P-component (SAP) selectively binds to immobilized or bound forms of C-reactive protein (CRP).

The two homologous human pentraxins, C-reactive protein (CRP) and serum amyloid P-component (SAP), specifically bind to each other only when the CRP is in an immobilized form bound to one of its ligands or to an antibody. CRP did not bind to immobilized SAP. The binding of SAP to immobilized forms of CRP was Ca(2+)-dependent and of sufficient affinity to occur in the presence of serum or purified serum proteins. SAP bound preferentially to a synthetic peptide corresponding to the Ca(2+)-binding region of CRP. Monoclonal antibodies to a synthetic peptide corresponding to the Ca(2+)-binding region selectively inhibited the binding interaction. Proteolytic cleavage of CRP between residues 146 and 147 within the Ca2+ binding region abolished the SAP-binding site; however, the intact subunits of the pentameric CRP were capable of binding SAP. The significance of the binding interaction is that it may serve as the basis for localization of SAP to sites of tissue damage or repair, sites where CRP is selectively deposited.

Characterization of an immune response.

The characterization of any detected antibodies provides detailed information that can be critical to understanding the significance of an immune response. The BIAcore immunoassay provides a straightforward means of characterizing many aspects of the immune response including antibody concentration, specificity, binding affinity, and the presence of isotypes. One important aspect of the immune response is determination of neutralizing capability, which requires a biological assay. The ultimate clinical significance of an immune response can only be fully understood when data from antibody characterization are coupled with clinical data from the patient. Some of the factors that can contribute to the clinical significance of an immune response are: (i) magnitude of the immune response (concentration of antibodies detected); (ii) duration of the immune response (continuous antibody production or sporadic and not sustained); (iii) correlation with any adverse events; (iv) correlation with a change in pharmacokinetics (either mediating sustained circulation or enhanced clearance of the drug); (v) biological neutralization of the drug; (vi) biological neutralization of an endogenous protein. Full characterization of the immune response requires the incorporation of antibody assays, pharmacokinetic assays, and clinical data.

Binding and immunological properties of a synthetic peptide corresponding to the phosphorylcholine-binding region of C-reactive protein.

A synthetic peptide corresponding to amino acid residues 47-63 of human C-reactive protein (CRP) was synthesized and evaluated for its ability to bind phosphorylcholine (PC) and to react with mAb specific for the PC-binding region of CRP. The PC-binding peptide displayed Ca2(+)-independent binding specific for PC and was able to compete against CRP for PC in the presence of Ca2+ ions. The synthetic peptide, like CRP, binds to the extracellular matrix protein fibronectin and the basement membrane protein laminin. The PC-binding peptide was recognized by those mAb generated against the intact CRP molecule that bind at, or near, the functional PC-binding region. In addition, several mAb to the T-15 idiotype present on mouse antibodies specific for PC, recognize an epitope(s) on the PC-binding peptide. Therefore, the 17 amino acid synthetic peptide shares both functional binding activity and antigenicity with the corresponding functional region within the CRP molecule.

Biosynthesis of the erythromycin macrolactone and a rational approach for producing hybrid macrolides.

The three eryA genes involved in the formation of the polyketide portion of the macrolide antibiotic erythromycin in Saccharopolyspora erythraea, appear to be organized in a single transcriptional unit on the basis of the results of gene disruption experiments. An insertion sequence-like element of lower G + C content separates eryAI from eryAII. The organization of the enzymatic domains present in the eryA-encoded multifunctional polypeptides, determined by computer-assisted analysis, is presented. This has enabled the determination of a putative dehydratase domain. A rational approach for producing novel macrolides by introducing selected changes in polyketide synthase genes is outlined. The isolation of a lactone intermediate resulting from an early synthesis step in macrolactone formation is also presented.

Detection and characterization of antibodies to PEG-IFN-alpha2b using surface plasmon resonance.

Some patients treated with type I interferon (IFN) preparations develop neutralizing antibodies that may abrogate any clinical benefit. We have a new complex of polyethylene glycol12000 and IFN-alpha2b (PEG-IFN-alpha2b) in clinical trials and need to be able to detect any antibodies formed specifically against the complex. We have, therefore, devised a method based on measurement of surface plasmon resonance (SPR) in the BIACORE 2000 apparatus. PEG-IFN-alpha2b is anchored to one flow cell on the sensor chip, IFN-alpha2b to another, and PEG to a third. A 20 microl serum sample flows in turn through the three cells, which are optically scanned. Any antibodies in the serum bind to the corresponding immobilized antigen, and a change in the optical signal is generated. With appropriate specific reagents, their immunoglobulin isotype can be similarly established. The automated assay can quickly test numerous sera. Very little serum is needed, and the assay is reliable and precise and can detect low-alphaffinity antibodies.

Conduction aphasia in multiple sclerosis: a case report with MRI findings.

Aphasia is an uncommon manifestation of MS, which is somewhat surprising because various disconnection syndromes, such as conduction aphasia, would be expected to occur with some regularity in this white matter disease. We present a case study of an MS patient with conduction aphasia associated with a large white matter lesion underlying the left supramarginal gyrus.

Preictal pseudosleep: a new finding in psychogenic seizures.

BACKGROUND AND OBJECTIVE: The diagnosis of psychogenic seizures (pseudoseizures) may be difficult and usually rests on video-EEG monitoring. We observed that pseudoseizures often arise out of a state that we termed preictal pseudosleep. The objective of this study was to investigate this potential new sign in pseudoseizures. METHODS: We prospectively studied all patients who underwent noninvasive monitoring over a 10-month period. Patients were monitored for a duration of 1 to 19 days (mean 4.9), and were divided into two groups: pseudoseizures and epileptic seizures. Patients with both conditions were excluded. Preictal pseudosleep was defined as a state that resembled normal sleep by behavioral criteria alone (i.e. patient motionless and eyes closed), while EEG showed evidence of wakefulness (alpha rhythm, active EMG, and rapid eye movement). This state had to be sustained for at least 1 minute before clinical onset. RESULTS: Patients had 1 to 25 (mean 7) clinical events recorded. Preictal pseudosleep was seen in 10 of 18 patients with pseudoseizures and in none of 39 patients with epileptic seizures, yielding a sensitivity of 56% and a specificity of 100% for pseudoseizures. CONCLUSION: Because of a high specificity, preictal pseudosleep may be a useful adjunctive finding to support the diagnosis of pseudoseizures.

Side of seizure focus predicts left medial temporal lobe activation during verbal encoding.

OBJECTIVE: Functional MRI (FMRI) was used to investigate the effect of medial temporal lobe (MTL) pathology on activation of language encoding areas in patients with temporal lobe epilepsy (TLE). METHODS: Whole-brain FMRI was obtained. Twenty-eight patients with either left TLE (LTLE) or right TLE (RTLE) performed a semantic decision task alternating with an auditory perceptual task. RESULTS: Activation of language areas in the frontal and parietal lobes was similar in both groups, with no group differences in the total number of active voxels. However, the RTLE group showed much stronger activation of the left MTL, including the hippocampus, parahippocampal gyrus, and collateral sulcus, than did the LTLE group. CONCLUSIONS: Activation of the left MTL during semantic encoding discriminates patients with RTLE and LTLE. This FMRI technique may potentially be of use in determining memory lateralization and for predicting the side of seizure focus in TLE.

Determination of language dominance using functional MRI: a comparison with the Wada test.

We performed functional MRI (FMRI) in 22 consecutive epilepsy patients undergoing intracarotid amobarbital (Wada) testing and compared language lateralization measures obtained with the two procedures. FMRI used a single-word semantic decision task previously shown to activate lateralized language areas in normal adults. Correlation between the two tests was highly significant (r = 0.96; 95% CIs 0.90 to 0.98; p < 0.0001). These results validate the FMRI technique and suggest that "active" areas observed with this semantic processing task correspond to those underlying hemispheric dominance for language. This strong correlation observed supports the view that language lateralization is a continuous rather than a dichotomous variable. In addition to lateralization information, FMRI consistently demonstrated focal regions of activity in lateral frontal and temporo-parieto-occipital cortex. These functional maps may be helpful in defining the boundaries of surgical excisions.

Validation parameters for a novel biosensor assay which simultaneously measures serum concentrations of a humanized monoclonal antibody and detects induced antibodies.

This report documents the validation of an assay using BIAcore 2000 that, with a single injection of mouse serum, allows the quantitation of a humanized monoclonal antibody and can also detect the presence of antibodies directed against this humanized antibody. The important components required for the validation of biosensor assays including precision, accuracy, linearity, stability of the immobilized ligand, specificity and sensitivity are addressed. The tandem assay that is used as a model for biosensor validations is accomplished by flowing each sample across the surface of two flowcells in sequence. The first flowcell has the antigen that the humanized mAb was generated against immobilized while the humanized mAb itself is immobilized on the second flowcell. The quantitation component of this assay is precise and accurate with a limit of quantitation of 1 microg/ml in mouse serum samples. Any antibodies directed against the humanized mAb can be detected and also characterized as to isotype. This unique assay can be performed with as little as 10 microl of serum which is then diluted ten-fold prior to analysis. The small sample requirement allows analysis of individual mouse serum samples rather than requiring the use of pooled samples from multiple mice. A further advantage of this assay is the automation capability which allows unattended operation.

Biphasic response of the regional lymphatics in the normal lymphocyte transfer reaction.

BACKGROUND: Initially developed for histocompatibility testing, the normal lymphocyte transfer (NLT) reaction involves the intradermal injection of allogeneic lymphocytes from one individual to another. Because of the unique kinetics of the immunological response to allogeneic lymphocytes, the NLT reaction has been considered an informative system for the analysis of transplant immunity. METHODS: In this study, we used bilateral efferent lymph duct cannulations in sheep to examine the regional lymphatic response to the NLT reaction. Our studies used monoclonal antibodies to define lymphocyte population dynamics and DNA flow cytometry to reflect lymphocyte proliferative responses. RESULTS: The results confirmed a biphasic NLT reaction. An unexpected finding was the marked differences between the early and late NLT responses. The early response was characterized by T-lymphocyte proliferation, as reflected by S-phase DNA, which was comparable in both the NLT-stimulated and contralateral control efferent lymphocytes. This bilateral proliferative response was observed in both CD4+ and CD8+ lymphocytes. In contrast, the late response was restricted to the efferent lymph from the NLT-stimulated lymph node. Dual-parameter flow cytometry demonstrated that the dominant component of this unilateral NLT response was CD8+ lymphocytes. CONCLUSIONS: These results suggest important functional distinctions between systemic and regional lymphatic responses to intradermal alloantigens.

A prospective study of hepatitis C virus infection in renal allograft recipients.

Hepatitis C virus (HCV) is the predominant cause of posttransplant non-A, non-B hepatitis among renal allograft recipients. Prior studies evaluating the impact of HCV in kidney transplantation have been retrospective in design and based largely on changes in serum transaminases. We studied a group of HCV-infected end-stage renal disease patients prospectively with pretransplant liver biopsies and close virologic and biochemical follow-up posttransplant. Fourteen patients have been followed a mean of 11.6 +/- 5.6 months posttransplant (range, 5-21 months). Six had changes of chronic hepatitis on pretransplant liver biopsy while 8 showed only mild histologic abnormalities. Circulating viral titers increased several-fold over baseline levels during posttransplant follow-up. Viral replication was particularly enhanced immediately following a course of antilymphocyte therapy. Although all patients showed a 2-3 fold increase in alanine aminotransferase (ALT) following transplantation, there were no association noted between pretransplant liver histology, the use of FK506 and/or cyclosporine-based immunosuppression, and the magnitude of ALT change posttransplant. The only clinical outcome found to differ significantly was a higher incidence of cytomegalovirus infection among patients with chronic hepatitis. All patients are alive with functioning grafts. There have been no episodes of fulmiinant or subfulminant liver failure. We conclude that HCV-infected patients can be safely transplanted with excellent short-term follow-up. Continued monitoring with sequential liver biopsies will be needed to define the long-term course of HCV infection in an immuno-suppressed population.

Immunoblastic lymphoma of donor origin in the allograft after lung transplantation.

Posttransplant lymphoproliferative disorders (PTLD) are EBV-associated lymphoid neoplasms that are caused by the uncontrolled growth of EBV-infected B lymphocytes. The clinical presentation of PTLD can range from benign polygonal lymphoproliferative disorders to aggressive monoclonal immunoblastic lymphomas. In this report, we describe a seronegative lung transplant recipient who developed an immunoblastic lymphoma 4 months after lung transplantation from a seropositive donor. The neoplastic cells expressed B lymphocyte markers (CD19+, CD20+, sIgM+, kappa+) as well as the EBV antigen EBNA-2. A cell line with similar cytologic features spontaneously grew from in vitro cultures of the patient's peripheral blood mononuclear cells. The cell line and the lymphoma were EBV+, expressed a similar spectrum of B cell surface proteins, and had the donor's HLA haplotype. Analysis of immunoglobulin gene rearrangements and viral terminal repeat sequences revealed that the cell line and the tumor represented distinct B cell clones. Cultured peripheral blood mononuclear cells were restimulated in vitro with the EBV transformed cell line and tested for cytolytic activity. The host T cells demonstrated high levels of cytolytic activity against the tumor cell line that was abrogated by the addition of a anti-monomorphic HLA class I monoclonal antibody (mAb) (W6/32). These studies indicate that cells of donor origin can persist in the transplanted organ and may lead to an EBV-associated posttransplant lymphoma.